The records of 20 Alaskan Native patients with primary hepatocellular carcinoma (PHC) diagnosed in the 11-year period 1969-1979 were reviewed. The annual incidence of PHC was found to be high among Alaskan Native males and especially high among Alaskan Eskimo males (7.6 and 11.2 per 100,000 respectively) in comparison to Greenland and Canadian Eskimos and US white males. Familial and geographic clustering of PHC patients was noted in areas known to be hyperendemic for hepatitis B virus (HBV) infection. A bimodal age distribution among PHC patients occurred with peaks at 15-25 years and 40-65 years. A high prevalence of hepatitis B surface antigen (HBsAg) in serum of patients in the younger age group suggests that HBV infection might be a factor associated with the development of PHC in young Eskimos. PHC in Alaskan Natives is apparently not closely associated with alcoholic cirrhosis.